#1
I have an Ibanez S470 (ZR tremolo system)

When using the whammy bar all strings stay in tune apart from the G string. Also even when the nut is tightened if I turn the Tuning peg the G string will still change pitch even though it is tightened well. Anyone know what the problem could be and how i'd go about fixing it?
#2
is the lock down pad sitting down properly on top of the string.

or

your string might not be in the nut slot properly

or

the string has cut into the nut slot/ lock down pad creating enough of a gap for the string to slip through (baby joel is better explaining this one)